Conventional methods for filling synthetic resin (e.g., polyethylene terephthalate) bottles with contents such as juice beverages and tea include the one called “high temperature filling” in which a bottle is filled with the content at a temperature of, for example, about 90° C. to sterilize the content and the bottle and then, immediately capped and sealed. Since the bottle is sealed and subsequently cooled in the high temperature filling, the inside of the bottle is placed under a significantly reduced pressure. For this reason, measures are taken to prevent the appearance of the bottle from undergoing unsightly deformation by providing the trunk portion with an area (so-called a reduced pressure absorbing panel) that is easily deformable or by allowing the bottom portion to be displaced toward the inside of the bottle (for example, refer to Patent Literature 1). When the bottom portion is imparted with a reduced pressure reducing function as in Patent Literature 1, design flexibility is enhanced because there is no need to provide the reduced pressure absorbing panel in the trunk portion, which attracts attention as the bottle appearance. Moreover, since there is no need for such a deformable reduced pressure absorbing panel, the trunk portion advantageously maintains its surface rigidity and exhibits excellent shape retention.